future rust, future dust
by closingdoors
Summary: 'It still makes her ridiculously happy to see this, to know that after everything they went through they both made it out, alive, and happy, and safe, with her perfect son now a wonderful new a addition to their lives.' COMPLETE.
Forget the horror here
Forget the horror here  
Leave it all down here  
It's future rust and it's future dust

 **\- Spanish Sahara, Foals**

* * *

 _I haven't written for this fandom in just under a year, but after all of the recent news, I needed something that would make me feel as though, after everything she has been though, Kate Beckett gets the happy ending she deserves. Pretend they beat LokSat somehow or that it never happened for this fic to work. Enjoy._

* * *

Strips of sunlight make their way through the cracks of the blinds, the wooden flooring beneath her feet delightfully cooling as Kate strips her t-shirt and pulls on one of the new bikini tops she'd bought for their time away. A stringy red thing that is bold compared to her jean shorts, probably the least she's worn around the place since she'd given birth. She turns and studies herself in the mirror, hands tracing over her stomach. No way as firm or as flat as before, but nothing that she hasn't been losing – albeit slowly – whenever she finds the time to work out.

After she knots the bikini at the back of her neck, she pulls her hair up into a messy bun, glancing behind by at Castle who continues to sleep blissfully, the sheets drawn down around his hips. She smiles to herself as she drifts past him, taking the stairs slowly and trailing her hand along the wall. Downstairs it's lighter, the windows free of blinds and she grabs a glass and pours herself some orange juice before stepping outside, toes wiggling against the grass and the early morning light beating down on her skin. She takes a moment to simply enjoy the quiet, the peace, and waits until she's finished the glass to go back inside.

In the room beside theirs, she finds Mason just beginning to wake, a wail already threatening to break free. She scoops him from his crib and hushes him, dusting kisses against his thin brown hair. He lets out one stubborn cry anyway. She lays him on the changing table, dropping his onesie into the laundry basket and freeing him of his soiled diaper. He attempts to roll over – something he's only started doing over the past week – so she keeps a steady hand on his stomach while she reaches for a new diaper and some wipes.

By the time she carries him out of his nursery, freshly changed and now in a tiny t-shirt and shorts, he's gurgling happily, head resting against her shoulder as he gnaws on his own fist. She washes a pacifier of his that they haven't managed to lose in the sink of the kitchen before replacing his fist with it. She takes a moment to kiss the top of his head, smiling a little at that newborn baby smell as her chest tightens. The fierceness of her devotion to Mason had startled her when he had first been born. It really had been like lightning, that kind of love, just like Castle had told her all those years ago.

It's still too early to feed him yet – one of the things that had surprised her after Mason had been born was just how much Castle had insisted on keeping everything scheduled – so she slathers his cheeks, nose and legs with sun screen, which makes him smile, and takes him outside with her, sitting while holding him on the grass and watching the rolling waves of the sea. Their place in the Hamptons really is beautiful.

"I think you'd like the sea," she tells Mason, letting him grip one of her fingers. "Your grandma, my mom, loved it, even though she was a city girl."

"There you are."

She glances over her shoulder to see Castle shuffling towards them, still a little sleepy, rubbing at his eyes. She smiles when he sits beside them, leaning forward to kiss her, the early morning breeze teasing her shoulders lightly. One of his palms settles low on her back, warm, as she leans into his side.

"You're up early," she comments as he takes Mason from her arms, greeting his son with a smile.

"The place was suspiciously quiet. It's unsettling, I'll have you know."

She laughs, pressing a kiss to his shoulder. "It's _peaceful_."

He wrinkles his nose, holding Mason out in front of him. Their son simply stares at him, quite possibly the only person in their family not to protest his antics, as he pulls a face.

"You think it's weird too, don't you, Mason?" He asks. Mason blinks. "You know, I will get that first laugh out of you someday."

She rolls her eyes as he begins telling their son awful jokes, stretching her arms out behind her slightly so that she can lean back a little, face turned up to the morning sun. It's the first bit of quiet they've had since Mason had been born – just over three months ago – and as much as she loves him, and his ridiculous family, she's needed this for weeks. It's what sparked their impromptu visit to the Hamptons this weekend, had them packing their bags yesterday afternoon and arriving late in the evening. She'd thought that their lives would be hectic looking after Mason, instead it had been a mess of trying to look after him while dealing with Martha – who had insisted on moving back in temporarily to help – and Alexis, who tried to help but more than often interrupted their peace. The boys and Lanie, too, seemed to be under the impression that they needed help, and they had barely had much alone time with their son since. The only one who hasn't crowded them so far is her father.

Kate smiles, lowering herself until she is laying with her back flat against the grass. Her father. It still makes her smile, remembering the way he had looked when he had stepped through the hospital door after she had given birth. His eyes focused on the bundle in her hands. The way he held his grandson so reverently that first time, every time. The others had been loud with him, Martha especially, so excited to greet Mason to their family. He had been quiet. Thankful. Kissed her forehead softly, smiling, even as Lanie appeared in the doorway and squealed, waiting impatiently to hold her godson.

It's not that she's ungrateful for the way everyone had wanted to help – it makes her heart riot in her chest to think of how much her son is loved by everyone they know. Sometimes, though, she just wants to be like this, with the man she loves and the son they share. The two people she cares about most in this world.

"What time's everyone coming tomorrow?"

She peels one eye open to peer up at him. "Six. I don't know what you were thinking inviting them all, there isn't enough space for everyone to sleep."

Castle shrugs. "We're only short two beds. We can shove some of them on the couches."

Sighing, she sits up, reaching for Mason who is beginning to fuss. "I'm gonna go feed him."

Castle stands with her, stretching, before letting his hands trail over her naked waist. "You know, I think Mason could do with a nap after…"

She rolls her eyes, batting his hands away. "Castle, he _just_ woke up."

Kate glances back at him as she heads towards the house, catching him watching her ass as she walks away. He's ridiculous.

* * *

Slipping her shorts off by the pool, Kate dips one foot in the water, testing its warmth. It's warm enough, so she slowly lowers herself in, holding Mason to her chest. His small chubby legs kick against her hip a little, eyes widening when she dips him low enough for the water to drift around his shoulders. She grins at him, murmuring nonsense, and he splashes his hands against the water, squealing. Kate is sure her heart tumbles in her chest.

She feels the water ripple as Castle slips into the pool, his hand resting on her hip as he reaches them. He laughs when Mason splashes them again.

"First time I tried to do this with Alexis, she screamed," he tells her, crossing his eyes when Mason looks up at him, making the baby smile.

"Really?"

"Oh, yeah. I did everything I could to prepare her for it, too – she _loved_ baths, so when she hit about six months I figured, why not?" He shakes his head, laughing. "She screamed the minute I got her in the water, and no matter how many times I tried to calm her down or make her play she'd just scream. I don't think I took her back until she was at _least_ two."

Kate laughs, tipping her head back, feels him press a kiss against her jaw and grin.

"How did she react the second time?"

"Oh, she loved it," he says, huffing. "Oooh, what if Mason is secretly half merman?"

"Castle, I did not give birth to anything other than a human."

"That's what the government _want_ you to think."

When she only rolls her eyes in response, he gasps, practically bouncing.

"Oh, wait, babies _love_ this," he says, before crouching in the water to blow bubbles.

Mason's eyes go wide, his legs kicking frantically, mouth opening to let out a peal of laughter.

Castle splutters, choking, as she gathers Mason closer to her. Her own eyes must be wide as saucers as she suddenly forgets how to breathe. Mason's laughing only grows louder as he watches Castle struggle for breath, one small hand smacking against her arm.

"He's..."

"Laughing," she finishes, smiling wide, unwilling to let her eyes stray from her son. He brings her so much joy.

He stops the second Castle is able to breathe again, instead entertaining himself by making small splashes as she and Castle continue to stare at him, mouths practically hanging open cartoon-style.

"Best. Swim. Ever," Castle declares.

* * *

Soon after they swim, they put Mason down for his first nap after bathing him. He's practically asleep by the time they slip him into pajamas, snuffling a little as Castle sets him down in the crib.

Castle tugs on her bikini top, lets the strap ping against her skin even as she elbows him.

"Worth it," he says at her glare, practically stepping on her feet as he follows her into their en suite.

He's already undoing the knots of her bikini top as she reaches to turn the shower on. It falls with a wet slap to the floor when the water begins to run and turns back to him, intent on hooking her fingers into his swimming trunks and letting them fall too. Instead his mouth is on hers instantly, warm and soft and just a _little_ hurried. The best kind of kiss. She sighs, drifting into him, his warm palms traveling down to circle her hips. She finds herself melting into him as his fingers dip beneath her bikini bottoms and send them falling down her legs. As some sense of rational thought comes back to her, she finds the waistband of his trunks, rids him of them before wrapping a hand round the back of his neck and pulling him back into the shower with her. She has not had nearly enough time alone with him recently.

"Why, Captain Beckett," he mumbles again her lips. "I thought you said you have things to do."

"Yeah, you," she mutters impatiently, drawing a thigh up and over his hip.

He laughs.

And then her hand travels down.

* * *

Kate hums, stretching out on the couch that evening, watching Mason attempting to grab the toys above him as he lies in his play gym. Castle sits beside her, letting her settle her head in his lap, his arm splaying along the back of the couch. She reaches up to let her nails drift against the palm of one of his hands. She's still pleasantly stuffed from dinner, drowsy and lethargic as he turns his serious gaze to her.

"Kate?"

"Hm?"

She twists a little to look up at him.

"I love you."

She smiles. "Right back at you."

"No, I mean…" He shrugs, reaching out to twine one of his hands with hers. "I love you. I love that we can just be here, like this, with our son. Safe."

Frowning a little, Kate sits up, so that she can swing a leg over his lap, knees resting either side of his hips as she settles back on his thighs.

"Me too, Castle," she murmurs softly. She leans in to kiss him softly, his palms wrapping around her bare thighs, tracing circles with his thumbs.

She wonders, sometimes, whether after all this time, he truly understands just how much he means to her. He has given her so much happiness – she's fought for it too – has given her a safe place and family to call home, a place to sleep late at night with a deep-rooted sense of security settling within her. He's given her Mason, her _son._ It still takes her breath away, the fierce way he loves her, so intent on giving her everything she wants and more. Does he know, will he ever really understand just how fiercely she loves him too?

"Me too," she repeats again when they part, leaning her forehead against his, content.

* * *

The next morning she wakes a little later than usual, hand reaching across the empty space beside her. The mattress is still a little warm, his imprint still lingering, and she rubs at her eyes before opening them slowly. One glance at the clock tells her that it's almost ten. She lifts her eyebrows in surprise.

Sighing, Kate gets to her feet, running a hand through her messy hair as she peers into Mason's nursery. Her little boy, like her husband, is nowhere to be seen. She takes the stairs and finds them in the kitchen, where Castle is trying to convince Mason to try a slice of banana. Mason's mouth remains firmly closed, watching her approach them over his father's shoulder.

"Castle. He's not even four months old yet," she says, rolling her eyes, stealing the baby away from his arms.

She smiles down at Mason, pulling a silly face in an attempt to make him laugh again. She's rewarded with his own gummy smile. It's enough.

Castle shrugs, tossing the banana piece into his mouth and chewing. "Thought I'd try. You never know, our genetics might be so superior that we might have created a superhuman. Like a _Captain America_ type superhuman."

Kate raises her eyebrows before shifting Mason to her other shoulder, pointing at the patch of drool he had left behind.

"Point taken."

* * *

Martha and Alexis are the first to arrive that night. Castle is staring at the barbecue he pulled out from god knows where, trying to figure out how to work it, as she checks herself in the mirror before she answers the mirror. The sundress reaches her knees, swaying a little as she holds Mason on one hip and opens the door to greet them with the other.

"Oh, there he is!" Martha is reaching for Mason before she's already through the door. Alexis laughs behind her, meeting Kate's eyes. It's only been two days. "Katherine, you look gorgeous, darling."

"Thank you, Martha," passing her Mason and kissing her on the cheek. "Rick's trying to fire up the barbecue."

Alexis rolls her eyes. "He never learns," she mutters, kissing Beckett's cheek briefly before heading out the back, no doubt to help Castle.

"Oh, he's _such_ a sweetheart," Martha exclaims for the thousandth time since he had been born. As she heads off to sit with him in the front room, Kate drags their bags inside, heading upstairs to drop them both in their rooms.

She heads for one of the hallway windows that overlooks the garden. Castle has – with Alexis's help – managed to set the barbecue up. He wraps his arm around his daughter's shoulder, squeezing. She finds herself biting her lower lip. Even now that they _have_ a kid, seeing the fatherly side to him still turns her on. A little. Not that she'd ever tell him that.

Once she's back downstairs, she fetches Martha a glass of wine. Her mother-in-law manages to balance her grandson and the glass as they head out to join Castle and Alexis on the porch.

Castle reaches for her the moment the evening breeze hits her skin, arm winding round to settle on her waist. Martha and Alexis sit, Alexis reaching over to let her younger brother's fist grip her fingers, a smile shared between both redheads. She feels the arm around her tighten and she turns into Castle, smiling, her own arms snaking around so that she can hold him for a moment.

Ryan and Esposito harass Castle for food the minute they arrive. Jenny, with Nicholas and Sarah Grace trailing after her, and Lanie are happy to sit with Martha and Alexis, fussing over Mason. Her son seems to enjoy the attention, watching them all curiously with a smile.

"Finally," Ryan and Esposito say in unison as Castle finishes cooking the his first (unburnt) burger, before fighting over whoever gets it. She slips past them and presses up onto her toes, resting her chin on Castle's shoulder.

"Okay?" She murmurs.

He shifts a little, until he can press a kiss to her cheek. "Okay. You want a burger?"

"Please."

Castle drops the burger into the bun, dropping a slice of cheese on top. Ryan and Esposito both reach for it but he twists to her, dropping it onto the paper plate she snagged from the side. Their jaws drop as she kisses Castle before dropping back down onto flat feet.

"Thanks, babe," she says, winking.

"Yo, that's no fair," Esposito protests.

"Yeah, Castle, if we knew we had to sleep with you to get the first burger…"

Smirking, Kate moves away as they all begin to bicker between themselves, watching Sarah Grace as she peers at Mason, asking Jenny if she can swap Nicholas for him.

Her father arrives a little later than the others, he had had to travel from their cabin to get there. She is pleasantly buzzed when he arrives, the glass of wine she'd had – her tolerance is still pathetic after her pregnancy – making the tips of her fingers tingle. She stoops to hug him, smiling when he almost immediately asks after Mason.

"We're all out on the porch," she says, hesitating a little in the doorway when she spots the multitude of empty beer bottles and half-finished bottles of wine sitting on the table. Her dad simply squeezes her hand.

"Jim!" Castle turns away from the barbecue to hold his hand out, shaking Jim's in greeting. "You hungry?"

"I am, actually," her father says, stepping away to head over to him.

"The boring salad stuff is over _there_ ," Castle points to one of the tables they'd set up, making a face. "There's some sodas there too. The good stuff is right here."

"It looks great, Rick," her father compliments, and she moves away, satisfied that he is comfortable for now, eventually managing to steal Mason away from Lanie.

She regroups with Castle and her father with Mason in her arms. Her dad places his plate down immediately, hot dog forgotten, all shy soft smile. He glances at her hesitantly, as if he's afraid to ask, and she passes Mason to him without saying a word. Jim looks down at the little boy, unable to wipe the smile off of his face, even when he starts gnawing on his grandfather's thumb. It still makes her ridiculously happy to see this, to know that after everything they went through they both made it out, alive, and happy, and safe, with her perfect son now a wonderful new a addition to their lives.

"He looks a lot like you did when you were young, Katie," he tells her.

"Really?" She asks, leaning into Castle's side. She's not been able to see much of herself in Mason just yet, too preoccupied with his bright blue eyes just like Castle's and hair the same shade as his.

"Oh, yeah, your hair used to stick up like this too," Jim tells her, running a finger along Mason's head. "Your nose was a button nose as well – that was the thing that changed most about you."

"I didn't know that," she murmurs, reaching out to stroke the soft skin of Mason's cheek with her thumb.

"It happened when you were a toddler. Your mom thought it was a funny transition."

Her chest gets tight and she takes a deep breath in through her nose, slowly letting it out through her mouth. Castle rubs her shoulder soothingly and she reaches for Mason, taking him from her father's arms with the need to be by her son suddenly. She cradles him close, closing her eyes and rocking him slightly. Oh, how she loves him.

* * *

Mason fusses when it gets too late, wailing as her father shushes and rocks him, growing a little panicked when he doesn't stop. Castle reaches Mason before she does, saving Jim from his cranky cries, and she follows him back into the house, away from the tipsy adults. Mason quiets a little once they reach his nursery, as always. Castle rocks him gently as she watches, hands curling in his belt when she stands behind him.

"Everyone seems to be having fun. Your dad included," Castle says, twisting to peer at her. "Are you?"

Kate raises an eyebrow. "Do I look like I'm not?"

He blinks at her slowly, their son in his arms, her chin settling on his shoulder.

"No," he replies, smiling. "You look great, by the way."

Kate pushes up on her toes to kiss him. "Thank you."

He moves away then, placing Mason in his crib as their son drifts into sleep. She watches them both, heart pounding, biting her lip. He raises his eyebrows when he turns back to her, catching her look, snaking his arms around her waist and pulling her close to him.

"I want another baby," she confesses softly, wary of Mason sleeping.

"Now?"

She laughs, pressing her fingers against her lips. "Not _now._ But… someday."

Kate peers up at him shyly, heart hammering, but he's only watching her with that same amazed, dopey look he always gives her. He leans down to kiss her, pressing that smile against hers, and she hums, toes curling. It is a beautiful thing, knowing that they can make decisions like this, know that they are safe now.

He'd looked at her that way the day she had told him she was pregnant with Mason. He hadn't been planned, exactly. They'd discussed kids as a vague idea for the future, something they'd shelved for a little while until suddenly it had become their reality. The minute she had seen that smile of his and that look in his eyes after she'd blurted out _I'm pregnant,_ she knew they'd always be okay.

"Maybe we should get some practice in," Castle teases, hands curving round to find her ass. She rolls her eyes even as warmth spills through her stomach. "Right now."

"I think people would notice if we were gone for too long."

"I can be quick."

"You shouldn't boast about that, babe."

He groans, kissing her one last time before releasing her, hand slipping down to take hers. She squeezes his as they leave the nursery, taking the stairs together.

"I'm surprised you haven't tried to set your illegal fireworks off yet."

He glances at her, pausing. "Am I allowed to admit I have those when I'm married to you _and_ have two other detectives as guests?"

"You've already set them up, haven't you?"

He grins. "Before anyone arrived."

Even as she pretends to chastise him, she lets him pull her back out to the garden. Martha is recounting a tale she's heard many times before about her time on broadway to Lanie, Jenny, and Ryan – a little loudly. Her father is sat engaged in conversation with Alexis, genuinely enjoying himself, and she spots Esposito chasing a giggling Sarah Grace and Nicholas around on the grass, something he'll probably pretend he didn't do in the morning when he's sober. She pauses for a second to breathe. This is her _family._ Her son is sleeping peacefully upstairs, her husband right beside her.

She looks up at him, heart caught in her throat.

Castle simply smiles.

They have time.

* * *

 **The End**


End file.
